Hydraulic concrete thin layer repairing machine spraying modified polymer mortar and preparation method thereof

Abstract

The invention relates to hydraulic concrete thin layer repairing machine spraying modified polymer mortar and a preparation method thereof. The mortar comprises a component A and a component B, the component A is powder and consists of Portland cement, a superfine mineral admixture, quartz sand, a polycarboxylic acid water reducing agent, a thixotropic agent and an expanding agent; the component B is a liquid material and consists of a polymer emulsion, an emulsion modifier and a preservative. The mortar prepared by uniformly mixing and stirring the component A and the component B can be mechanically sprayed, is simple and convenient to construct and has good anti-permeability and mechanical properties, the 28d bonding strength is greater than or equal to 2.5 MPa, the chloride ion permeation resistance grade reaches RCM-IV or above, the 28d abrasion resistance strength is greater than or equal to 12.0 hm < 2 > / kg, the strength loss rate after 200 times of freezing and thawing cycles is less than or equal to 8.0%, and the mass loss rate is less than or equal to 0.4%, so that the fusion of spraying constructability and high durability of the polymer mortar is realized; the method is suitable for efficient and large-area repair and reinforcement of hydraulic concrete, prolongs the service life of hydraulic buildings, reduces the rerepair rate, and promotes the efficient, environment-friendly and durable development of repair and reinforcement projects.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and relates to the technical field of efficient repair and reinforcement of defects such as cracking, powdering, efflorescence and shedding on the surface of hydraulic concrete under complex operating conditions coupled with multiple factors such as freezing and thawing, impact abrasion and corrosion, and specifically relates to a hydraulic concrete thin layer repair machine-sprayed modified polymer mortar and a preparation method thereof. Background Art

[0002] Under the influence of factors such as water erosion, natural carbonization, freeze-thaw cycles, etc., hydraulic concrete is prone to problems such as concrete surface aging, peeling, cracks, leakage, etc., which seriously affect the safe operation and service life of the building. At present, my country has a large number of completed, under construction or renovated hydraulic structure projects that urgently need to take measures to carry out large-scale protection and repair and reinforcement.

[0003] Polymer mortar has been widely used in water conservancy project risk prevention and reinforcement, anti-seepage repair, anti-carbonization repair, etc. due to its excellent bonding, crack resistance, anti-seepage repair, and aging resistance. Traditional polymer mortar is generally constructed by manual scraping, which has low efficiency, uncontrollable manual factors, and difficult to ensure construction quality, making it difficult to meet the needs of large-scale rapid construction of hydraulic structures. The use of mechanical spraying can not only reduce labor costs and improve construction efficiency, but also improve the overall construction quality. Patent CN 110818361 A and Patent CN 109180128 A disclose two polymer repair mortars suitable for mechanical spraying. The mortars have good workability, thixotropy and crack resistance, but the 28d compressive strength does not exceed 12MPa, and the 28d tensile bond strength is up to 1.0MPa, which is difficult to meet the technical requirements for concrete structure reinforcement. Patent CN116947394 A discloses a machine-sprayable organic-inorganic composite reinforcement mortar and its preparation method. By introducing two polymers, glue powder and emulsion, and other functional additives, the mortar's adhesion and durability are enhanced. However, the mortar is mainly suitable for industrial and civil building repair and reinforcement, and it is difficult to meet the long-term waterproof and anti-seepage requirements of hydraulic structures. Patent CN 117822933 A discloses a hydraulic concrete high-performance repair mortar and its construction process. By adding polymer emulsion, glue powder and air entraining agent, the mortar's anti-seepage, anti-freeze and adhesion properties are improved, and by adding silicon powder and basalt fiber, the mortar's anti-abrasion performance is improved. However, observing its embodiments, it is found that the mortar consistency is only 35mm, which is difficult to meet the needs of mechanical spraying.

[0004] Therefore, in response to the above problems, there is an urgent need to develop a hydraulic structure repair and reinforcement mortar that can be mechanically sprayed and has high strength, high durability, adhesion, impermeability and crack resistance, so as to extend the design service life of the building, reduce the repair rate, and promote high-quality, green and circular development of water conservancy. Summary of the invention

[0005] The purpose of the present invention is to provide a hydraulic concrete thin layer repair machine-sprayed modified polymer mortar to address the deficiencies in the prior art, which can solve the problems of poor workability, low mechanical properties, low efficiency of manual spreading and pressing construction, and difficulty in ensuring construction quality of traditional polymer mortars, and achieve the synergy of the sprayable construction property and high performance of the polymer mortar, providing technical support for promoting the large-scale rapid construction of polymer mortars and improving the quality of hydraulic concrete repair and reinforcement projects.

[0006] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is: a hydraulic concrete thin layer repair machine spray modified polymer mortar, including component A and component B, wherein: Component A includes by weight: 350~550 parts of Portland cement; 10~50 parts of ultrafine mineral admixture; 350~700 parts of quartz sand; Polycarboxylate water reducer 0.05~0.5 parts; Thixotropic agent 0.5~2.5 parts; 10~40 parts of expansion agent; Component B includes by weight: 50-150 parts of polymer emulsion; 0.5~4 parts of emulsion modifier; Preservative 0.1~1 part.

[0007] As a preferred embodiment of the present invention, the silicate cement is P·O 42.5 ordinary silicate cement.

[0008] As a preferred embodiment of the present invention, the ultrafine active mineral admixture is composed of volcanic ash ultrafine aluminosilicate mineral powder material with an average particle size of 2 μm, a SiO2 content of ≥94%, and a 28d activity index of ≥115%.

[0009] As a preferred embodiment of the present invention, the quartz sand is a compound of 10-20 mesh quartz sand and 40-120 mesh quartz sand, and the weight ratio is: 10-20 mesh quartz sand: 40-120 mesh quartz sand = (30-60): (40-70).

[0010] As a preferred embodiment of the present invention, the thixotropic agent is one or a composite of hydroxypropyl methylcellulose ether, hydroxyethyl methylcellulose and hydroxypropyl starch ether.

[0011] As a preferred embodiment of the present invention, the expansion agent is a calcium sulfoaluminate-calcium oxide expansion agent.

[0012] As a preferred embodiment of the present invention, the polymer emulsion is a pure acrylate copolymer emulsion or a composite of one or more of silicone resin-acrylate copolymer emulsions, and the solid content is not less than 40%.

[0013] As a preferred embodiment of the present invention, the emulsion modifier is a composite of one or more non-ionic paraffin emulsion and unsaturated polyester resin emulsion, and the solid content is not less than 40%.

[0014] As a preferred embodiment of the present invention, the preservative is one or a combination of Brobol (2-bromo-2-nitropropane-1, 3-propanediol), BIT (1, 2-benzisothiazolin-3-one), and Kesong (2-methyl-4-isothiazoline-3-one and 5-chloro-2-2methyl-4-isothiazoline-3-one).

[0015] In addition, the present invention also provides a method for preparing a hydraulic concrete thin layer repair machine spray-modified polymer mortar: According to the above weight ratio, the raw material components of component A are put into an automatic mixer and mixed by physical and mechanical stirring for 4 hours. After mixing evenly, component A is obtained; the raw material polymer emulsion, emulsion modifier, and preservative of component B are mixed evenly in proportion, and a high-speed shearing emulsifier is used to high-speed shear at a rate of 7000r / min for 10 minutes, and then the sheared emulsion is ultrasonicated for 10 minutes using an ultrasonic disperser to remove the bubbles generated during the high-speed shearing process, thereby obtaining component B. When used, component A and component B are stirred evenly, and an appropriate amount of water is added to mix and stir. After adding water and stirring, the consistency of the mortar is controlled within the range of 105mm~115mm, the stirring speed is not less than 48r / min, and after stirring for 4~6 minutes, the hydraulic concrete thin layer repair machine spray modified polymer mortar is obtained.

[0016] The technical principles of the present invention are as follows: Using one or more of the composites of non-ionic paraffin emulsion and unsaturated polyester resin emulsion as emulsion modifier can inhibit the initiation and expansion of cracks during the consolidation process, effectively reduce the surface and internal pores of the mortar, improve the density of the mortar, and enhance the strength and anti-seepage and waterproof effects of the mortar. At the same time, it can reduce the range of the interface transition zone and enhance the bonding performance of the mortar. Using one or more of the composites of hydroxypropyl methylcellulose ether, hydroxyethyl methylcellulose, and hydroxypropyl starch ether as thixotropic agent can interweave and wrap with the network structure of cement hydration products to achieve inter-layer slip and improve the internal adhesion of the system. The cohesive effect ensures the anti-sagging property of the slurry after mechanical spraying on the wall; the cohesiveness of the polymer emulsion and the volcanic ash filling effect of the ultrafine mineral admixture are utilized to make the pore size of the slurry finer, reduce the permeability and porosity, limit the entry of external moisture, and effectively improve the bonding performance, waterproof and anti-seepage performance, and chloride ion penetration resistance of the mortar. At the same time, the film-forming effect of the polymer effectively binds the moisture inside the mortar, reduces the expansion stress caused by water freezing, and enhances the anti-freeze performance; an appropriate amount of calcium sulfoaluminate-calcium oxide expansion agent is added to exert its filling effect, reduce the shrinkage rate, and reduce the risk of mortar cracking.

[0017] The beneficial effects of the present invention are: (1) Strong spray construction performance: The mortar consistency is controlled at 105~115mm, and it is not easy to hang after spraying.

[0018] (2) High strength, crack resistance, impact and wear resistance: 28d compressive strength ≥45MPa, 28d flexural strength ≥12MPa, 28d shrinkage rate ≤0.05%, 28d impact and wear resistance ≥12.0h•m 2 / kg.

[0019] (3) High bonding strength: The bonding strength of the untreated surface after 7 days is ≥1.5MPa, and the bonding strength after 28 days is ≥2.5MPa; the bonding strength after water immersion and 25 freeze-thaw cycles is ≥2.0MPa.

[0020] (4) Excellent waterproof, anti-seepage and anti-chloride ion penetration effects: 28d anti-seepage pressure ≥ 2.0MPa, water absorption rate ≤ 2.4%, and anti-chloride ion penetration level above RCM-IV.

[0021] (5) Excellent anti-freeze performance: After 200 freeze-thaw cycles, the mortar strength loss rate is ≤8.0%, and the mass loss rate is ≤0.4%.

[0022] The hydraulic concrete thin layer repair machine-sprayed modified polymer mortar provided by the present invention is suitable for mechanical spraying, and the maximum thickness of one-time spraying can reach 10mm without sagging. It has good workability and high strength, high adhesion and high durability, and can improve construction efficiency and quality at the same time, effectively increase the service life of hydraulic concrete structures, and provide technical support for the problem of large-scale repair and reinforcement of water conservancy projects. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with specific embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments.

[0024] Example 1 The hydraulic concrete thin layer repair machine spray modified polymer mortar of this embodiment, component A is calculated by weight as 450 parts of silicate cement, 20 parts of ultrafine mineral admixture, 275 parts of 10-20 mesh quartz sand, 275 parts of 40-120 mesh quartz sand, 0.25 parts of polycarboxylic acid water reducer, 1 part of thixotropic agent, and 20 parts of expansion agent, which are uniformly mixed; component B is calculated by weight as 70 parts of polymer emulsion, 1 part of emulsion modifier, and 0.1 part of preservative, and then a high-speed shear emulsifier is used to high-speed shear for 10 minutes at a rate of 7000r / min, and then the sheared emulsion is ultrasonicated for 10 minutes using an ultrasonic disperser to remove bubbles generated during the high-speed shearing process, so as to obtain the present invention; component A and component B are stirred evenly, and an appropriate amount of water is added and mixed and stirred for 4 minutes, and the stirring speed is not less than 48r / min, so as to obtain the present invention.

[0025] Example 2 The hydraulic concrete thin layer repair machine spray modified polymer mortar of this embodiment, component A is calculated by weight as 350 parts of silicate cement, 50 parts of ultrafine mineral admixture, 300 parts of 10-20 mesh quartz sand, 300 parts of 40-120 mesh quartz sand, 0.2 parts of polycarboxylic acid water reducer, 1.5 parts of thixotropic agent, and 10 parts of expansion agent, which are uniformly mixed; component B is calculated by weight as 60 parts of polymer emulsion, 0.8 parts of emulsion modifier, and 0.1 parts of preservative, and then a high-speed shear emulsifier is used to high-speed shear for 10 minutes at a rate of 7000r / min, and then the sheared emulsion is ultrasonicated for 10 minutes using an ultrasonic disperser to remove bubbles generated during the high-speed shearing process, so as to obtain the present invention; component A and component B are stirred evenly, and an appropriate amount of water is added and mixed and stirred for 4 minutes, and the stirring speed is not less than 48r / min, so as to obtain the present invention.

[0026] Example 3 The hydraulic concrete thin layer repair machine spray modified polymer mortar of this embodiment, component A is calculated by weight as 500 parts of silicate cement, 30 parts of ultrafine mineral admixture, 300 parts of 10-20 mesh quartz sand, 200 parts of 40-120 mesh quartz sand, 0.3 parts of polycarboxylic acid water reducer, 1 part of thixotropic agent, and 10 parts of expansion agent, which are uniformly mixed; component B is calculated by weight as 80 parts of polymer emulsion, 1.5 parts of emulsion modifier, and 0.2 parts of preservative, and then a high-speed shear emulsifier is used to high-speed shear for 10 minutes at a rate of 7000r / min, and then the sheared emulsion is ultrasonicated for 10 minutes using an ultrasonic disperser to remove bubbles generated during the high-speed shearing process, so as to obtain the present invention; component A and component B are stirred evenly, and an appropriate amount of water is added and mixed and stirred for 4 minutes, and the stirring speed is not less than 48r / min, so as to obtain the present invention.

[0027] Example 4 The hydraulic concrete thin layer repair machine spray modified polymer mortar of this embodiment, component A is calculated by weight as 550 parts of silicate cement, 40 parts of ultrafine mineral admixture, 200 parts of 10-20 mesh quartz sand, 200 parts of 40-120 mesh quartz sand, 0.5 parts of polycarboxylic acid water reducer, 0.5 parts of thixotropic agent, and 40 parts of expansion agent, which are uniformly mixed; component B is calculated by weight as 100 parts of polymer emulsion, 2 parts of emulsion modifier, and 0.3 parts of preservative, and then a high-speed shear emulsifier is used to high-speed shear for 10 minutes at a rate of 7000r / min, and then the sheared emulsion is ultrasonicated for 10 minutes using an ultrasonic disperser to remove bubbles generated during the high-speed shearing process, so as to obtain the present invention; component A and component B are stirred evenly, and an appropriate amount of water is added and mixed and stirred for 5 minutes, and the stirring speed is not less than 48r / min, so as to obtain the present invention.

[0028] Example 5 The hydraulic concrete thin layer repair machine spray modified polymer mortar of this embodiment, component A is calculated by weight as 500 parts of silicate cement, 50 parts of ultrafine mineral admixture, 270 parts of 10-20 mesh quartz sand, 180 parts of 40-120 mesh quartz sand, 0.4 parts of polycarboxylic acid water reducer, 2.5 parts of thixotropic agent, and 20 parts of expansion agent, which are uniformly mixed; component B is calculated by weight as 95 parts of polymer emulsion, 1.5 parts of emulsion modifier, and 0.3 parts of preservative, and then a high-speed shear emulsifier is used to high-speed shear for 10 minutes at a rate of 7000r / min, and then the sheared emulsion is ultrasonicated for 10 minutes using an ultrasonic disperser to remove bubbles generated during the high-speed shearing process, so as to obtain the present invention; component A and component B are stirred evenly, and an appropriate amount of water is added and mixed and stirred for 6 minutes, and the stirring speed is not less than 48r / min, so as to obtain the present invention.

[0029] Application Examples The following is the performance of the present invention: The modified polymer mortar for hydraulic concrete thin layer repair machine spraying is a two-component material. When using, the two components can be evenly mixed, and the water-binder ratio is 0.29. The slurry properties prepared with the above mix ratio are shown in Table 1, and the test method is carried out in accordance with the relevant provisions of JGJ / T 70-2009 "Basic Performance Test Method of Building Mortar", JG / T 336-2011 "Polymer Cement Mortar for Repair of Concrete Structures", JG / T 289-2010 "Polymer Mortar for Reinforcement of Concrete Structures", SL 352-2020 "Test Procedure for Hydraulic Concrete", and GB 50164-2011 "Concrete Quality Control Standard".

[0030] Table 1 Test results From the above test results, it can be seen that the hydraulic concrete thin layer repair machine-sprayed modified polymer mortar provided by the present invention has good spray construction performance, mechanical properties, bonding properties, impermeability, frost resistance, abrasion resistance and chloride ion penetration resistance, meets the technical index requirements of Type A mortar in JG / T 336-2011, meets the requirements of Type II mortar in JG / T289-2010, and according to GB 50164-2011, the chloride ion penetration resistance grade reaches RCM-IV or above.

[0031] The mortar of the present invention is suitable for mechanical spraying construction, has good anti-sagging performance after being sprayed on the wall, and has no cracking or hollowing phenomenon on the surface after hardening, thereby effectively improving the construction efficiency and the construction quality.

[0032] Although the present invention lists some of the test results of the embodiments as disclosed above, they are not intended to limit the present invention. Anyone familiar with this art can make various changes or modifications without departing from the spirit and scope of the present invention, such as the 28d activity index of the ultrafine mineral admixture ≤ 115%, the solid content of the polymer emulsion > 40%, etc. The effect after such adjustment is predictable, and such changes also fall within the scope defined by the protection scope of the claims of this application. Therefore, the protection scope of the present invention shall be based on the protection scope defined by the same or equivalent technical features of the claims of this application.

Claims

1. A hydraulic concrete thin layer repair machine spray modified polymer mortar, characterized in that: It comprises component A and component B; wherein, Component A includes by weight: 350~550 parts of Portland cement; 10~50 parts of ultrafine active mineral admixture; 350~700 parts of quartz sand; Polycarboxylate water reducer 0.05~0.5 parts; Thixotropic agent 0.5~2.5 parts; 10~40 parts of expansion agent; Component B includes by weight: 50-150 parts of polymer emulsion; 0.5~4 parts of emulsion modifier; Preservative 0.1~1 part.

2. The hydraulic concrete thin layer repair machine spray modified polymer mortar according to claim 1, characterized in that: The silicate cement is PO 42.5 ordinary silicate cement.

3. The hydraulic concrete thin layer repair machine spray modified polymer mortar according to claim 1, characterized in that: The ultrafine active mineral admixture is composed of volcanic ash ultrafine aluminosilicate mineral powder material with an average particle size of 2 μm, SiO2 content ≥ 94%, and 28d activity index ≥ 115%.

4. The hydraulic concrete thin layer repair machine spray modified polymer mortar according to claim 1, characterized in that: The quartz sand is compounded by 10-20 mesh quartz sand and 40-120 mesh quartz sand, and the weight ratio is: 10-20 mesh quartz sand: 40-120 mesh quartz sand = (30-60): (40-70).

5. The hydraulic concrete thin layer repair machine spray modified polymer mortar according to claim 1, characterized in that: The thixotropic agent is one or a composite of hydroxypropyl methylcellulose ether, hydroxyethyl methylcellulose and hydroxypropyl starch ether.

6. The hydraulic concrete thin layer repair machine spray modified polymer mortar according to claim 1, characterized in that: The expansion agent is a calcium sulphoaluminate-calcium oxide expansion agent.

7. The hydraulic concrete thin layer repair machine spray modified polymer mortar according to claim 1, characterized in that: The polymer emulsion is a pure acrylate copolymer emulsion or a silicone resin-acrylate copolymer emulsion, or a composite of several of them, and the solid content is not less than 40%.

8. The hydraulic concrete thin layer repair machine spray modified polymer mortar according to claim 1, characterized in that: The emulsion modifier is a composite of one or more nonionic paraffin emulsion and unsaturated polyester resin emulsion, and the solid content is not less than 40%.

9. The hydraulic concrete thin layer repair machine spray modified polymer mortar according to claim 1, characterized in that: The preservative is one or a composite of Bropol (2-bromo-2-nitropropane-1, 3-propylene glycol), BIT (1, 2-benzisothiazolin-3-one), and Kesong (2-methyl-4-isothiazoline-3-one and 5-chloro-2-2-methyl-4-isothiazoline-3-one).

10. A method for preparing the hydraulic concrete thin layer repair machine spray modified polymer mortar according to any one of claims 1 to 9, characterized in that: According to the weight ratio, the raw material components of component A are put into an automatic mixer and mixed by physical and mechanical stirring for 4 hours. Component A is obtained after being evenly mixed; the raw material polymer emulsion, emulsion modifier and preservative of component B are evenly mixed in proportion, and a high-speed shear emulsifier is used to high-speed shear at a rate of 7000r / min for 10 minutes, and then the sheared emulsion is ultrasonicated for 10 minutes using an ultrasonic disperser to remove bubbles generated during the high-speed shearing process to obtain component B; component A and component B are stirred evenly, and an appropriate amount of water is added to mix and stir. After adding water and stirring, the consistency of the mortar is controlled within the range of 105mm~115mm, the stirring speed is not less than 48r / min, and after stirring for 4~6min, the hydraulic concrete thin layer repair machine spray modified polymer mortar is obtained.

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